docs: def get_body(name):
      """Retrieve a given body orbits and parameters
  
      Args:
          name (str): Object name
      Return:
          Body:
      """
  
      try:
  
          body, propag = _bodies[name.lower()]
          # attach a propagator to the object
          body.propagate = propag.propagate
      except KeyError as e:
          raise UnknownBodyError(e.args[0])
  
      return body